Nuts

David Baddiel sets out to make sense of some apparently puzzling topics. In the first programme of this series, after receiving suggested topics on social media, David tries to understand why nuts have hard shells. He visits the Royal Botanic Gardens in Kew to meet the head of the arboretum, and a nut tree; and speaks to Thor Hanson, the author of 'The Triumph of Seeds'. On his journey to understanding David finds himself discussing evolution, fruit, badger poo, concrete and absent-minded squirrels. Producer: Giles Edwards.